title: Retrospective assessment of exposure to static magnetic fields during production and development of magnetic resonance imaging systems.
abstract: At present, the relationship between chronic exposure to static magnetic fields (SMF) and health effects is unclear. We developed a task-based deterministic model for estimating historical electromagnetic field exposure from the static B-field (B0) of magnetic resonance imaging (MRI) systems, for a cohort of employees working at an MRI systems development and production facility. Technical maps describing the spatial distribution of fringe fields of B0 surrounding different types of MRI systems of various core strengths were exploited to derive estimates of static B0 exposure as a function of distance from the bore of the MRI system. Detailed information on tasks performed per exposed job and other model determinants were acquired through face-to-face interviews and used to derive base estimates of most recent exposure (2009) for each job title. The model was partially validated with actual exposure measurements. The exposure estimates from the deterministic model were used to construct a job-exposure matrix that will enable estimation of cumulative exposures for each cohort member. The generic approach described for estimating chronic MRI-related SMF exposure makes it universally applicable in other studies investigating health effects of MRI-related SMF exposure.
authors.affiliation: Environmental Epidemiology Division, Institute for Risk Assessment Sciences, Utrecht University, PO Box 80.178, Utrecht 3508 TD, the Netherlands;
authors.forename: Suzan
authors.initials: S
authors.lastname: Bongers
authors.forename: Yvette
authors.initials: Y
authors.lastname: Christopher
authors.forename: Hans
authors.initials: H
authors.lastname: Engels
authors.forename: Pauline
authors.initials: P
authors.lastname: Slottje
authors.forename: Hans
authors.initials: H
authors.lastname: Kromhout
mesh_terms: D000465:Algorithms; D004574:Electromagnetic Fields / Q000009:adverse effects*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D066192:Manufacturing Industry; D008962:Models, Theoretical; D016273:Occupational Exposure / Q000032:analysis*; D011834:Radiation Monitoring / Q000379:methods; D012044:Regression Analysis; D012189:Retrospective Studies
keywords: exposure modeling; job-exposure matrix; magnetic fields; occupational exposure assessment; static magnetic fields